It is well known to support a pair of car wash brushes having substantially vertical axes of rotation on booms or “knuckles” which can pivot about vertical axes of rotation adjacent to a vehicle treatment area so as to engage and scrub a vehicle exterior. These wrap-around brushes typically employ a power cylinder to urge the brushes to their outermost or extended positions which are generally adjacent the centerline of the vehicle treatment area. When a vehicle passes between the brushes, the cylinders are deactivated allowing gravity to move the brushes back toward a retracted position on the boom or knuckle. In the retracted (or not fully extended) position, the brushes can engage the side surfaces of the vehicle. When the vehicle has traveled a sufficient distance, the power cylinder can be reactivated urging the brushes toward the extended or outermost positions so that they can engage and clean the rear surface of the vehicle. These types of brushes have suffered from various difficulties, including with respect to proper programming of the timing of the initiation of the outward re-extension of the brushes to accommodate vehicles of different lengths and widths. This has resulted in insufficient cleaning of the rear surfaces of many vehicles.
Various attempts have been made to try and solve these and other issues with prior wrap-around brushes. Specifically, wrap-around brushes have been developed that include a ball pivot at the upper end of the rotary brush to allow the brush to pivot away from a vertical position upon contact with a vehicle such that the brush is disposed at an angle with respect to vertical. This arrangement provides some improved cleaning of the vehicle side surfaces and also helps minimize damage to mirrors and antennas. However, these brushes do not provide sufficient cleaning of the rear vehicle surfaces, particularly in vehicle washes with higher speed conveyors. This is in part due to the fact that their configuration does not allow the brush to contact the vehicle rear exterior for a long enough dwell time. These brushes also suffer from an ability to effectively clean angled surfaces.
It would therefore be desirable to provide an improved wrap-around brush that addresses the above limitations.